"The individual has just been arrested. It is important to calm people. There is nothing to suggest there are others involved," prosecutor Vincent Macq told the Belga news agency.
Officials said the man had fled on foot after guards fired warning shots. No casualties were reported.
An AFP journalist at the scene said the presumed assailant abandoned the damaged vehicle in a field nearby.
A military bomb squad had arrived at the site as well as a SWAT team.
A local TV station said that pupils at a nearby school were told to remain indoors.
Officials told AFP no immediate motive for the attack was known.
The Flawinne base in the central Belgian city is home to a commando battalion of 650 soldiers that take part in NATO operations and peacekeeping missions.
The incident stirred memories of recent deadly attacks, including the killing of four people at the Jewish museum in central Brussels in 2014 by a jihadist gunman.
